Thread: sbc 305

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I have a 305 h.o got it bore 30 I have 1992 vortec heads and I have intake to go with it it has a 350 crank in it I am going to order keith black pistons I was wondering whats the best cam to get I want it to chop hard I am trying to atleast get 300hp the motor is going in an 84 2 door box chevy car I am getting 373 gears put in will this get me 300hp I also have a 700r4 transmission thanks I just need a little help I was told this setup will give me 300hp but I wana be sure

BEST write up on the 305 I have seen.
Don't know if it'll help but there ya go...joe




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I'v had a 305 in my 37 chevy truck for many years and had a lot of fun with it. I had it bored .060 over with a extreme energy cam 218/224/ dur. at .050 with a Edelbrock dual plane intake, 600 cfm carb, sanderson headers, The heads had a mild porting. This is putting out 303HP . I have highway gears of 2:76 and with a 350th tranny I can still spin the wheels. Kick it into passing gear and it pushes me back into the seat. My truck only weighs 3,000 lbs. and I get 18-20 MPG.

Welcome to CHR!

The 305 is often seen as a “red-headed-stepchild” but they can be built to 300 horsepower without too much work. The 305 was the smallest production bore for small block Chevy engines at 3.736”. Even with your new bore (3.766”) you’re still a long way from a stock 350 bore of 4.00”. While both engines share the same stroke, journal bearing size and rod length, on average, the 305 crank is two pounds lighter than a stock 350. As such, you’ll need to have your rotating assembly carefully balanced or at about twenty-five hundred RPM your engine will shake like a squirrel trying to pass a petrified acorn. 305 engines are still plentiful and you can get a brand new crank from Summit for under $200 with free shipping - http://www.summitracing.com/parts/es...make/chevrolet
I wouldn’t mess with the 350 crank as it brings no value to the build.

Make sure your block is prepped correctly and have a machinist deck it and give you the measurement – stock is 9.025. Take that measurement along with the combustion chamber volume of the heads (stock are in the 55-58cc range) and the gasket thickness and then get some help to pick pistons that will get you between 8.5 and 9.5:1 – no more as you’ll have issues with iron heads and todays pump gas.

The Vortec heads are good.

A roller kit cam from Howard’s (with lifters) from Summit will set you back $600 http://www.summitracing.com/parts/hr...make/chevrolet

Performer RPM (make sure it’s for Vortec’s) and a Quadrajet will bring you 300 horsepower.

Use stock HEI distributer.

700R4 with 2200-2400 stall will be fine.

Have fun and let us know what you decide!
Glenn